Ship and associated methods of formation with vessels having connectable hulls

ABSTRACT

A ship and associated methods of formation with vessels having connectable hulls. In an example embodiment, a method of operating a ship includes providing a plurality of vessels over water, each comprising at least two spaced-apart hull sections defining a cavity when the vessel is afloat. Each hull section on each vessel is configurable as a portion of a coupling mechanism with fore and aft portions of each hull section reduced in width relative to intermediate hull section portions. Pairs of hull section fore portions may be lapped with and connected to pairs of hull section aft portions on different vessels to form complete coupling mechanisms which connect vessels to one another. Accordingly, the plurality of vessels can form a single assembly and power can be transferred between vessels to move the vessels through water in a tandem arrangement.

RELATED APPLICATIONS

This application claims priority based on U.S. Provisional PatentApplication Ser. No. 60/909,850 filed Apr. 3, 2007.

STATEMENT REGARDING FEDERALLY SPONSORED DEVELOPMENT

Development for this invention was supported in part by Contract No.N00014-05-0347, awarded by the United States Department of the Navy.Accordingly, the United States Government may have certain rights inthis invention.

FIELD OF THE INVENTION

This invention relates generally to ships and, more particularly, tomaritime designs and methods of transport.

BACKGROUND OF THE INVENTION

The transportation industry provides a wide variety of modes and routeswith which to meet diverse demands. Selection can be based on numerousfactors, including required delivery speed, security and the influenceof transportation cost on the price of goods and services. When rapid,time-critical movement is required over a long distance, e.g., thousandsof miles, air service has been the norm for both passenger and cargotransport. By way of example, rapid deployment of large militaryoperations can require significant levels of air transport to placeequipment and personnel where they are needed when they are needed. Onthe other hand, when commodity freight is being moved large distances,selection of the transportation mode is more cost sensitive, but oftenlimited by the availability of low-cost choices. Depending on points ofdeparture and destination, multiple low cost choices may be available,but there is often a need to accept the slowest transit speeds tominimize transportation expense and thereby assure cost competitivegoods and services. The cost of freight transport is highly dependent onoperational costs.

When moving large volumes of freight between different continents, seatransport has been the predominant mode due to cost, while passengertransportation is predominantly by air. Commerce along some large inlandwaterways may be predominantly by barge or freighter, being limited tocommodity products or large cargo which is cost prohibitive orimpractical to ship over land. Generally, the choice of watertransportation for long distance shipment implies acceptance ofrelatively slow delivery speed. When multiple transportation modes areavailable to reach a freight destination the competitiveness of themaritime industry has been challenged. Other modes may be less fuelefficient but are still cost competitive while also providing greaterspeed and flexibility. For example, the rail and trucking industries areoften capable of more quickly delivering products to final destinationswhile cargo shipped by water must often be transferred to rail cars ortrailers to effect final delivery.

In order for transportation by water to be more competitive it would bedesirable to improve speed and further reduce transportation costs.However, operating costs, often increase with speed, particularly forfreightliners. Such limiting factors are rooted in the limits ofachievable hydrodynamic efficiencies for vessel designs. It has longbeen known that the efficiency of movement through water is a functionof a ship's length to beam (L/B) ratio. There have been continualefforts to improve the design of ships with high L/B ratios foroperation at relatively high speeds. Several classes of vessels havebeen so optimized.

Limitations in achievable performance stem from inherent structuralissues associated with performance under high structural loads andbending moments such as experienced in high sea states. Strength andflexure issues associated with long, slender ships are addressed withprovision of a more robust, typically heavier, longitudinal girdersystem relative to that required for relatively short ships. Generally,the length of the ship dictates the size and weight of the longitudinalgirder system. With advanced analysis capabilities to model behaviors ofhulls under dynamic loading, and considering the length of the ship as asingle beam for modeling of behavior, girder systems must be ofsufficient stiffness and mass to assure acceptable operation in thepresence of expected bending moments. It is desirable to develop designsfor long and slender vessels (e.g., with L/B>10) which avoid thecomplexities and added mass conventionally required, as such can enablea more cost efficient ship which can operate more economically. Suchimprovements can render maritime transportation more suitable for avariety of commerce and non-commercial needs. What is needed is a set ofsolutions which render maritime operations faster, more flexible, andmore cost efficient. With such greater capabilities maritimetransportation can be a more acceptable alternative to transportationneeds that otherwise must be addressed with air or land-based systems.

BRIEF DESCRIPTION OF THE INVENTION

In accord with an embodiment of the invention a method of operating aship includes providing a plurality of vessels over water, eachcomprising at least two spaced-apart hull sections defining a cavitywhen the vessel is afloat. Each hull section on each vessel isconfigurable as a portion of a coupling mechanism with fore and aftportions of each hull section reduced in width relative to intermediatehull section portions. Pairs of hull section fore portions may be lappedwith and connected to pairs of hull section aft portions on differentvessels to form complete coupling mechanisms which connect vessels toone another. Accordingly, the plurality of vessels can form a singleassembly and power can be transferred between vessels to move thevessels through water in a tandem arrangement.

According to another embodiment, a ship includes a power system and aplurality of vessels. Each of the vessels includes at least twospaced-apart hull sections defining a cavity when the vessel is afloat.When vessels are connected to one another they provide a series ofinterconnected cavities forming a chamber, with each vessel capable ofoccupying a first draft when afloat without aid of the power system anda second draft smaller than the first draft with aid of the powersystem. Each hull section on each vessel is configurable as a portion ofa coupling mechanism with fore and aft portions of each hull sectionreduced in width relative to intermediate hull section portions.Accordingly, pairs of hull section fore portions and pairs of hullsection aft portions on different vessels can be lapped and connectedwith one another to form complete coupling mechanisms each operable toconnect one vessel to another vessel so that the plurality of vesselscan form a single assembly. Power can be transferred between vessels tomove the vessels through water in a tandem arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of thedrawings wherein:

FIG. 1 provides a partial perspective view of a ship according to anembodiment of the invention;

FIG. 2 is a view of the ship of FIG. 1 in a view showing an underside ofthe ship;

FIG. 3 illustrates a series of vessels coupled to one another to form aship according to the embodiment of FIG. 1;

FIG. 4 is a partial perspective view illustrating hull portions andother select elements forming an exemplary mechanism that effectscoupling of the vessels shown in FIG. 3;

FIGS. 5 a and 5 b are partial plan views schematically illustratingportions of hulls associated with the vessels shown in FIG. 3;

FIG. 6 is a partial perspective view of an alternate configuration ofhull portions for effecting coupling of the vessels shown in FIG. 3.

FIG. 7 is a partial perspective view illustrating hull portions andother select elements of a coupling mechanism according to an alternateembodiment to effect a coupling of the vessels shown in FIG. 3;

FIG. 8 is a perspective view of a three dimensional model illustrating ahinge arrangement;

FIGS. 9A-9D are simplified plan and perspective views illustrating acoupling mechanism according to another embodiment;

FIGS. 10A-10E are side elevation views illustrating possible variationsin hull designs according to the invention;

FIGS. 11A through 11D are elevation views illustrating ship 10 invarious modes of operation;

FIG. 12 illustrates, in a side elevation view, the ship of FIGS. 1-4deployed as a surface effect ship; and

FIGS. 13A and 13B are elevation views of the ship shown in FIG. 12illustrating the bow and stern.

Like reference characters denote like or corresponding parts throughoutthe figures. In order to emphasize certain features relating to theinvention, certain features shown in the figures may not be to scale.

DETAILED DESCRIPTION OF THE INVENTION

Before describing in detail example embodiments according to theinvention, it is noted that the invention includes a novel andnon-obvious combination of elements and method steps. So as not toobscure the description, details of elements and steps pertinent to theinvention are emphasized in the figures and written description, withoutillustrating in the figures certain associated elements and steps whichare otherwise conventional or which will be readily apparent to thoseskilled in the art.

With reference to the simplified perspective view of FIG. 1, there isshown, according to one embodiment of the invention, an exemplary ship10 comprising multiple vessels 14 arranged in a serial assembly fortandem movement as one unit or ship. Adjacent ones of the vessels 14 areflexibly coupled to each other to allow variations in pitch of eachvessel. Yet the vessels are coupled in a manner allowing transfer ofmotive power from vessel to vessel, thereby enabling movement of theentire series of vessels in a controllable manner and as a single ship,e.g., somewhat analogous to movement of a railroad train comprising aseries of cars each coupled to another. The ship 10 includes a fore-mostvessel 14, designated 14 a, a rear-most vessel 14, designated 14 b, andmultiple intermediate vessels between the vessels 14 a and 14 b.Although only four vessels are shown in the figure the ship 10 mayinclude fewer or a larger number of vessels 14, e.g., ten or morevessels. As indicated for intermediate ones of the vessels 14, each ofthe illustrated vessels includes a hull portion 16 and a platformstructure 18 which may comprise multiple decks and superstructures. Likecomponents among the intermediate vessels as well as the vessels 14 aand 14 b are designated with like reference numbers.

As used herein to describe a feature of a ship, the term length refersto a distance measurable along a direction parallel with the dimensionof the ship or its hull which is substantially aligned with the primarydirection of intended ship motion or thrust; and the term width refersto a distance measurable along a direction normal to the length. Thelengths and widths of the vessels 14 may vary considerably. For purposesof providing an example range of dimensions, the lengths of commercialvessels according to the embodiments described may vary from less than30 m to over 300 m and the widths may vary from less than 20 m to over40 m.

FIG. 2 is a perspective view taken from beneath the ship 10 illustratingthat each hull portion 16 comprises a pair of opposing and substantiallyparallel catamaran hulls 20, each hull in a pair designated as astarboard hull 20 a or a port side hull 20 b. A lowest deck 22 of theplatform structure 18 is formed of individual decks 22-1, 22-2, 22-3etc. on different vessels 14 which are each connected between a pair ofthe hulls 20 a and 20 b. The surface of the deck 22 which faces downwardtoward the water, as well as the component surfaces of the decks 22-1,22-2, 22-3, etc. which face downward toward the water, are referred toas wet decks. Generally, the hull portion 16 of each vessel 14 has alength extending from a fore portion 24 to an aft portion 26 of thevessel. See FIG. 3. In this embodiment, all of the hulls 20 a extendalong a first straight axis A and all of the hulls 20 b extend along asecond straight axis A′ parallel to the axis A.

The ship 10 extends an overall length L, comprehending individuallengths of the plurality of hulls 20 a along the axis A and theplurality of hulls 20 b along the axis A′ among the multiple connectedvessels 14. Hulls 20 positioned along each axis extend substantiallytoward one another with nominal or minimal spacing therebetween toaccommodate required clearance for movement and sealing materials asdescribed herein. In other embodiments, hulls of different vessels thatare aligned along a common axis may be spaced substantially apart fromone another, e.g., by a meter or more with optional sealing materialssuch as a bellows arrangement, extending between the hulls of differentvessels to provide isolation of cavities formed between opposing hulls20 a and 20 b if it is desired to provide a pressure differentialbetween the cavities relative to atmospheric pressure. The ship length,L, extends from the ship bow 25, along the fore portion 24 of the vessel14 a, to the ship stern 28, along the aft portion 26 of the vessel 14 b.

The hulls 20 a and 20 b of each vessel 14 are parallel with one another,and each vessel 14 has a width B (see FIG. 5) measurable as the distancebetween the outside substantially parallel surfaces of opposing hulls,20 a and 20 b, i.e., as measured from an exterior-facing surface alongthe port side of one hull to an exterior-facing surface along thestarboard side of the opposing hull. For embodiments where each of thevessels in the ship has the same beam width, B, the ship may bedescribed as having a uniform beam width B.

The view of FIG. 2 illustrates that each pair of hulls 20 a and 20 b ofeach vessel 14 provides a cavity region 32 having an associated volumeof air when the vessel is on water. With the vessels 14 coupled in atandem arrangement, the series of cavity regions 32 are in opencommunication with one another to form a chamber 36, extending alongmultiple vessels 14, which is multiple times the volume associated withany individual cavity region. The illustrated chamber 36 extends fromthe ship bow 25 to the ship stern 28 and is substantially enclosed bythe series of hulls 20 a and 20 b in combination with a bow seal 40positioned along the bow 25 of the ship and a stern seal 44 positionedalong the stern 28 of the ship.

The vessels 14 forming the ship 10 may be coupled in a variety of waysdepending on the degrees of freedom desired for each vessel with respectto each adjacent vessel to which it is joined. Depending on how thevessels are coupled to one another, each vessel 14 may experience heave,or changes in pitch, yaw or roll, relative to an adjacent vessel, aboutthe point of coupling between the vessels. FIG. 3 illustrates a seriesof the vessels 14 coupled to one another in a configuration suitable foroperation of the ship 10. The perspective view of FIG. 4, illustrateselements of one exemplary coupling mechanism 50 that effects coupling ofthe first and second adjacent vessels 14-1 and 14-2 shown in FIG. 3.Portions of the hulls 20 a and 20 b positioned along the aft portion 26of the second vessel 14-2 are, respectively, each adapted to rotatablyengage with portions of the hulls 20 a and 20 b along the fore portion24 of the first vessel 14-1.

With respect to FIGS. 4 and 5 a, the vessels 14-1 and 14-2 are shown inspaced-apart relation for clarity of illustration. This illustrationshows additional components of the platform 18. Above the lowest deck 22there is an exemplary second deck 34 which includes a weather cover 38formed thereover. In this embodiment, when the coupling mechanism 50 isfully engaged the coupling is the interface between the two vessels,i.e., between the fore portion 24 of the first vessel 14-1 and the aftportion 26 of the second adjacent vessel 14-2. Each coupling mechanism50 comprises two couplings 50 a and 50 b, each of a three componenthinge-type arrangement. A fore region component on a hull on one vesselis connectable with an aft region component on a hull of another vesselwith a locking pin. See, also, FIG. 5 b. Each coupling 50 a, on thestarboard side of the vessels, comprises a first pin 54 a which links afore region 56 a of the hull 20 a of the vessel 14-1 to an aft region 58a of the hull 20 a of the vessel 14-2. This arrangement enables arotational, hinge-like movement of the hull fore region 56 a of thefirst vessel 14-1 about the pin 54 a and with respect to the aft region58 a of the vessel 14-2. Similarly, the couplings 50 b, each on the portside of the vessels 14-1 and 14-2, comprises a second pin 54 b whichlinks a fore region 56 b of the hull 20 b of the vessel 14-1 to an aftregion 58 b of the hull 20 b of the vessel 14-2. These pairs of threecomponent arrangements enable a rotational, hinge-like movement of thehull fore region 56 b of the first vessel 14-1 about the pin 54 b andwith respect to the hull aft region 58 b of the vessel 14-2.

The pins 56 a and 56 b may be stationary with respect to the aft regions(58 a, 58 b) while the fore regions (56 a, 56 b) rotate, but otherarrangements will be apparent. The coupling mechanism 50 is one ofseveral embodiments which can provide the ship 10 with a continuous, yetarticulated or jointed, first hull 60 a comprising the plurality ofhulls 20 a, e.g., along the axis A, and provide the ship 10 with acontinuous, yet articulated or jointed, second hull 60 b comprising theplurality of interconnected hulls 20 b, e.g., along axis A′. In thissense, the ship 10 is an articulated or jointed vessel. In otherembodiments the ship 10 may include one or more additional articulatedhulls, e.g., incorporating mechanisms 50, positioned between the hulls60 a and 60 b and extending the length L of the ship.

The general concept of an articulated vessel has been explored in thepast. See, for example, U.S. Pat. No. 3,938,461. However, priorimplementations have not provided a series of vessels which, whencoupled for tandem motion, collectively behave as a single ship. Forexample, the ship 12 can be steered and maneuvered as a single vesselalthough it comprises multiple vessels 14. Several embodiments of theinvention achieve this effect by allowing changes in pitch amongindividual vessels while constraining other motion such as roll or yaw.According to several embodiments, rotational movement and translationalmovement along certain axes is controlled or prohibited to prevent yawor roll while allowing rotational movement that enables changes in pitchin response to vertical bending moments. Thus individual vessels canundergo changes in pitch while limiting or prohibiting other motionsthat would result in undesirable behaviors. As an example, under highsea state conditions it may be most preferred to limit or fullyconstrain changes in roll and yaw among individual vessels whileallowing changes in pitch. On the other hand, on relatively calm inlandwaterways it may be desirable to allow individual vessels to undergochanges in both pitch and yaw while constraining changes in roll. Thefollowing examples illustrate a system which constrains changes in rolland yaw while allowing changes in pitch.

FIGS. 5 a and 5 b are simplified views of the pairs of hulls 20 a and 20b of the vessels 14-1, 14-2 and 14-3. FIG. 5 a is a plan view showingtwo pairs of hulls 20 a and 20 b in spaced-apart relation as they arebeing joined to provide a mechanically coupled arrangement of thevessels 14-1 and 14-2. The figures illustrate features of an exemplarydesign incorporating the coupling mechanism 50 to join the hulls 20 andform the larger hulls 60 a and 60 b of the ship 10. In this example, thehulls 20 of adjacent vessels are coupled to one another with the samemechanism 50 at each interface between two vessels 14 but combinationsof different coupling mechanisms, e.g., providing varying degrees offreedom, are contemplated. When the hulls 20 are coupled together withthe mechanism 50, a profile of substantially fixed width can bemaintained along the entire length of the two articulated ship hulls 60a and 60 b. One simplified example of a hull design and associatedcoupling mechanism 50 which results in the articulated hulls 60 a and 60b is now described. The hulls 20 a and 20 b are illustrated as thoughthey have each been formed with a pair of opposing vertical sidewalls sothat each of the four side walls are positioned in a plane parallel withthe other planes. It is to be understood that in other embodiments ofthe invention the hull sidewalls may have curvature with respect to suchplanes and with respect to the axes A and A′, and the hulls may includevarious symmetric or non-symmetric features. Numerous additionalvariations in hull design are contemplated while nonethelessincorporating the concepts shown in the simplified illustrations of FIG.5.

To effect the consistent profile of substantially fixed hull width alongeach of the axes A and A′, each of the hulls 20 has a uniform width Wover the majority of the hull length, wherein the width W is measurablefrom an outside plane surface 64 a of each hull 20 a to an inside planesurface 66 a of the same hull, and from an outside plane surface 64 b ofeach hull 20 b to an inside plane surface 66 b of the same hull; whileat both the fore regions and the aft regions of the hulls 20, the widthsof those portions of hulls on one vessel that rotate with respect toportions of hulls on adjoining vessels are reduced. As used herein withrespect to a hull 20, the term outside surface refers to a surface thatfaces outward or away from the ship 10, and the term inside surfacerefers to a surface that faces inward or toward another hull 20. For agiven vessel, the inside surface 66 a of the hull 20 a faces the insidesurface 66 b of the hull 20 b. With the portions of hulls that rotatewith respect to other portions of hulls and having reduced width, e.g.,widths reduced to W/2, the engaging portions which rotate with respectto one another can be lapped to create a combined width, e.g., W,thereby providing a substantially uniform overall width for each of thehulls 60 a and 60 b including about the region of overlap.

The fore regions 56 a of the hulls 20 a each include a plane outsidesurface portion 70 a (facing away from the vessel) and a plane insidesurface portion 72 a (facing the hull fore region 56 b) with a width,W/2, measured from the plane portion 70 a to the plane portion 72 a.Similarly, the fore regions 56 b of the hulls 20 a each include a planeoutside surface portion 70 b (facing away from the vessel) and a planeinside surface portion 72 b (facing the hull fore region 56 a) with awidth, W/2, measured from the plane portion 70 b to the plane portion 72b. The aft regions 58 a of the hulls 20 a each include a plane outsidesurface portion 74 a (facing away from the vessel) and a plane insidesurface portion 76 a (facing the hull aft region 58 b) with a width W/2measured from the plane portion 74 a to the plane portion 76 a.Similarly, the hull aft regions 58 b of the hulls 20 b each include aplane outside surface portion 74 b (facing away from the vessel) and aplane inside surface portion 76 b (facing the hull aft region 58 a) witha width W/2 measured from the plane portion 74 b to the plane portion 76b.

In view of the foregoing geometry, the fore regions 56 a and 56 b andthe aft regions 58 a and 58 b each have a profile width W/2 which ishalf of the otherwise uniform hull width W over the majority of thelength of the hulls 20. Consequently, with this reduction in hull widthat the hull fore and aft regions, the fore and aft regions can lap oneanother to form a hinge joint between vessels which results in a smooth,continuous transition region between adjoining hulls 20 having a widthW. In this example the width reductions along the individual fore andaft regions 56 a, 56 b, 58 a and 58 b, relative to the full hull width Ware abrupt, resulting in angled, notch-shape recesses which arereferenced in the figures as fore recesses 78 a and 78 b (adjacent thehull fore regions 56 a and 56 b, respectively, each extending along oneof the surfaces 72 a and 72 b), and aft recesses 80 a and 80 b (adjacentthe hull aft regions 58 a and 58 b, respectively, each extending alongone of the surfaces 74 a and 74 b) with the hull fore regions 56 a and56 b each extending toward one another a distance W/2 from a respectiveplane outside surface portion 70 a or 70 b.

The recesses 78 a and 78 b about the fore regions 56 a and 56 b can eachreceive one of the aft regions 58 a and 58 b, also of width W/2, and therecesses 80 a and 80 b about the aft regions 58 a and 58 b can eachreceive one of the fore regions, such that fore and aft regions formlapped pairs (56 a, 58 a) and (56 b, 58 b) with each surface 72 apositioned against a surface 74 a and each surface 72 b positionedagainst a surface 74 b. See FIG. 5 b. Although the surfaces 72 a, 72 b,74 a and 74 b are described as plane surfaces, it is contemplated thatsuch lapping of fore and aft regions of different hulls can be effectedwith surfaces that are not formed in parallel planes and such surfacesmay be angled, beveled or curved with respect to vertical or horizontalplanes and may include additional contours along surfaces which lap oneanother or along regions adjacent lapped surfaces.

A feature of the illustrated embodiment is that each lapped combinationof a hull fore region and a hull aft region, e.g. regions 56 a and 58 a,or regions 56 b and 58 b, provides a profile having a combined widthequal to the hull width W. This results in a substantially consistentwidth W along the entire length of each ship hull 60 a and 60 b.Although the hulls 60 a and 60 b have been described with opposing sidesof the same hull being substantially parallel to one another, and havingsubstantially constant widths W, this has been for simplicity ofillustration. Generally, opposing sides of the same hull may occupy nonparallel planes or may follow contours along the hull length or alongplanes orthogonal to a central axis along the length. Although the hulls60 a and 60 b have been described as having fore and aft regions havingindividual widths w/2 such that when lapped the combined widths equal W,other proportions may be preferred. For example, the aft regions of thehulls 20 may have reduced widths of W/3 relative to a full hull width Win portions thereof which lap while the fore regions of the hulls 20 mayhave a width (⅔)W relative to the full width W. The combined width ofthe two portions may still be W. Other proportions as well as angled andcontoured shapes are contemplated. While it is desirable that the lappedcomponents generally provide a width W. FIG. 6 is a partial perspectiveview of the hulls 20 according to an alternate configuration wherein thefore regions 56 a and 58 b are angled to receive the aft regions 58 aand 58 b.

FIG. 5 b is a partial sectional view of the vessels 14-1 and 14-2illustrating the pairs of hulls 20 a and pairs of hulls 20 b shown inFIG. 5 a. The view is taken along a plane passing through the pins 54 aand 54 b. Pairs of the hulls 20 a and 20 b are shown engaged to oneanother with a hinge pin 54 a connecting hull fore region 56 a to hullaft region 58 a and with a hinge pin 54 b connecting hull fore region 56b to hull aft region 58 b. The illustrated pins 54 a and 54 b are shownas extended a sufficient width into both of the hulls in a lapped pairto assure to securement and reliable rotational movement responsive toforces which change the pitch of the vessels. The pins 54 a and 54 b maybe of varied designs. In the illustrated embodiment the pins may befixedly secured to or through the fore regions 56 a and 56 b (or to theaft regions 58 a and 58 b) such that the aft regions may be swung, via ahinge arrangement, into place so that each pin passes into an aperturewithin an aft region. Alternately, the aft regions may include guides orangled slots for placing the pins at appropriate positions therein asthe aft regions are moved into the recesses 78 a and 78 b and the foreregions are moved into the recesses 80 a and 80 b. The pins 54 a and 54b may also be of the moveable or retractable type, controlled, forexample, by actuators or hydraulics or manual means. Such hinge designshave been used, for example, to connect a tug-barge unit, with the bowof the tug coupled to a stern notch of a cargo-carrying barge by meansof retractable pins. Such available hinge designs, available fromBludworth Cook and Intercontinental Manufacturing, have been used toallow one monohull vessel, i.e., a tug, to pitch with respect to anothermonohull vessel, i.e., a barge. Generally, the starboard and port sidesof one vessel may be fitted with pins which are initially in a retractedconfiguration and which are extended once the vessels are aligned forcoupling. Such hinge style couplings permit changes in pitch whileconstraining the vessels from separately undergoing changes in roll andyaw.

According to another embodiment, the perspective view of FIG. 6illustrates two spaced-apart vessels 14 a-1 and 14 a-2, functionallysimilar to the vessels 14, incorporating a variation of the couplingmechanism 50. The hull fore regions 56 a and 56 b each are formed withan angled wall surface 90 a or 90 b along the surfaces 72 a and 72 b(schematically shown in FIG. 5 a) to facilitate centering of the afthull portion 26 of the vessel 14 a-2 with respect to the fore hullportion 56 a of the vessel 14 a-1. To further assist with alignment andplacement of the pins 54 a and 54 b, each surface 90 a and 90 b includesan engagement slot 92 to guide movement of a pin to the desired position94. Once the pins are positioned for engagement, locking mechanisms,such as the rotatable mechanism 98 shown in FIG. 8, retain each pin inplace. Alternately, retraction-expansion mechanisms may further displaceeach pin along a longitudinal direction (i.e., along the direction ofthe width of the vessels) into receiving volumes, such as receivingcylinders, within the hull fore regions 56 a and 56 b. The receivingvolumes may include sealed bearings or other low friction assemblies tofacilitate continual rotational movement between the pins and the hullregions 56 a and 56 b. FIG. 6 also illustrates an optional, exemplaryseal 100 along an outside surface 74 a of a hull aft region 58 a.Generally seals of varying designs may cover any or all of the surfaces72 a, 72 b, 74 a and 74 b in varying degrees to reduce or minimizemovement of air through the interface between coupled vessels when thechamber 36 has a positive pressure. The seal 100 may be a brush seal ormay be formed of a synthetic woven material, e.g., polypropylene, or maybe of a rubber-like or low-friction material and may be inflatable,e.g., in an annular or semi-annular shape, to pneumatically vary thedegree of sealing.

FIG. 7 illustrates a further variation in design of the hull foreregions 56 a and 56 b with each incorporating a wing section 102rotatable about a pivot assembly 104. Each wing section includes anengagement slot 92 as described with respect to FIG. 6. Motion of thewing sections about the pivot assemblies may be powered.

The embodiments so far described include but are not limited to designswhich incorporate a split hull connection configuration, i.e., whereinthe fore and aft portions of adjoining hulls are reduced in width inorder to be lapped against one another and effect connection with a pin.See, for example, FIG. 5. Numerous other arrangements are contemplated.For example, the deck at the aft of one vessel may extend beyond thehull to connect directly with the deck or the hulls of another vesselvia, for example, retractable pins that extend from one of the decks.FIG. 8 is a perspective view of a three dimensional model illustrating ahinge arrangement connecting a lowest deck level 22 a along an aftregion 58 of one vessel with fore regions 56 of hulls 20 located on theport and starboard sides of a second vessel. FIG. 9A is a simplifiedplan view showing such an arrangement for two spaced-apart vessels 14b-1 and 14 b-2, functionally similar to the vessels 14, butincorporating another variation of the coupling mechanism 50. Forpurposes of illustrating features of this embodiment the figure showscomponents that are in different planes and which would not be visiblein a view taken along a single plane. Portions of the vessel hulls areshown at the fore regions 24 (see FIG. 3) of the vessels.

The vessel hulls, designated 120 a and 120 b differ from the hulls 20 aand 20 b in that they can be of substantially constant width over theentire length of each to form the ship hulls 160 a and 160 b. The hulls120 a and 120 b do not incorporate a lapped configuration wherein foreregions of hulls on one vessel are hinged directly to aft regions ofhulls on an adjoining vessel. Rather, the hull fore regions, designated156 a and 156 b and the hull aft regions 158 a and 158 b can be of thesame width, W, as the other portions of the hulls. At the fore ends 24of the vessels 14 b-1 and 14 b-2, the hulls 120 a and 120 b extendbeyond the deck 22, while at the aft ends 26 the deck 22 extends beyondthe hull aft regions, designated 158 a and 158 b. The hull fore regionsof the vessel 14 b-1 are designed to receive retractable-extendable pins154 a and 154 b which are mounted at the aft of the deck 22 of thevessel 14 b-2.

FIG. 9B illustrates fender material 164, e.g., an elastomer, applied toan end of a hull 120 a at the fore region 156 a and a P-seal 166 appliedalong the bow of the deck 22 between the fore regions 156 a and 156 b toreduce or minimize movement of air through the interface between pairsof coupled vessels when the chamber 36 has a positive pressure. FIG. 9Cillustrates further positioning of P-seal material 166 along the end ofa hull 120 b at the aft region 158 b to further reduce movement of airout from the chamber 36. FIG. 9D is a partial perspective view of theembodiment of FIG. 9A illustrating the fore region 24 of the vessel 14b-1 (without fender material and seals) and a receiving cylinder 162formed in the fore region 156 a of the hull 120 a into which a pin 154 amay slide to couple the deck of an adjoining vessel 14 b-2 thereto. Thecylinder 162 may include bearings to facilitate non-binding, lowresistance, rotational movement of the pin relative to the hull.

The illustrated embodiments address limitations in conventional shipdesign. Generally, as the length of a vessel increases, conventionaldesign practices have required that the structure be strengthened towithstand higher moments of loading. Vessels are designed to exhibitsufficient stiffness to counter, for example, vertical bending momentsdue to seaway. More generally, a large vessel can incur a combination oflow frequency wave-induced vertical bending moments (transverse with thelength of the hull) and higher frequency lateral forces resulting fromthe impact of waves against the hulls. There is a non-linearrelationship between increases in vessel length and the structural massthat must be added to the vessel in order to provide necessary stiffnessto the hull structure. This has made it especially costly to providevery long ships, and it has become accepted that, to meet structuralrequirements under the most adverse sea conditions, the mass per unitlength will increase as the overall length of a vessel is increased.Thus the need for the structure to withstand various types of stresseshas limited the ability to provide vessels which are both longer andmore lightweight. Without sufficient structural resilience a vessel canflex and oscillate in response to bending moments sometimes placing thehull out of alignment and possibly resulting in failure.

These conventional constraints are overcome by providing an articulatedship comprising multiple vessels flexibly coupled to one another fortandem movement. With regard to the exemplary hulls 60 a, 60 bcomprising multiple segments each formed of a catamaran-like hull 20 aor 20 b, a feature of the invention is that the length and beam width ofindividual hulls 20 can be based on desired performance parameters,including weight, buoyancy, operating speed and efficiency, while notlimiting the overall length of the ship. Thus the structuralrequirements for the hulls 60 that form the ship 10 are not primarilybased on the overall length of the hulls 60, but, rather, are largelybased on the length of the individual hulls 20 and design specificationsestablished for the individual vessels 14 which form the ship 10. Toovercome constraints relating to bending moments, the hulls areconnected to one another in a manner which allows for movement ofindividual ones of the vessels 14, so that the individual hulls 20 areresponsive to bending moments. For example, at the interface betweencoupled vessels there can be translational or rotational degrees offreedom which permit responsiveness of one or more vessels to externalforces. With the coupling mechanism 50, in one embodiment the ship 10allows for constrained movement of individual vessels in response tovertical bending moments, and thus there can be significant change invessel pitch. This allows the individual vessels to be displaced insteadof requiring the ship 10 having to behave as a rigid and more heavilybuilt structure. The vessels of the ship 10 can be displaced in responseto bending moments (e.g., induced by variations in the contours of awater surface) while a ship with a rigid hull would be designed towithstand such moments with less flexure.

As illustrated in FIGS. 2 and 4, the ship 10 may include a bow seal 40and a stern seal 44. In combination with these seals, the ship may befurther equipped to function as a Surface Effect Ship (SES), the designof which overcomes limitations of ship length and performance that havebeen characteristic of this vehicle class. The seal 100 of FIG. 6 andthe various other seals shown in the figures can facilitate retention ofair pressure (relative to surrounding ambient pressure) in the chamber36 to provide lift to the hulls 60 a and 60 b.

In the past, Surface Effect Ships have generally included fore and aftskirts about a single pair of rigid, parallel catamaran hulls tosufficiently enclose the air volume between the hulls and enablepressurization that results in formation of an air cushion for elevatingthe hulls. Generally, with respect to prior SES designs as well as theembodiments illustrated herein, an elevation of hulls in a SES withpressurized air is referred to as an on-cushion state. This is to becontrasted with an off-cushion state in which the elevation of the hullsdetermined by vessel buoyancy. An on-cushion configuration, relative toan off-cushion state, enables the ship to cruise at a relatively highspeed with relatively low water resistance.

In prior SES designs the hulls have been rigid girder systems extendingthe entire length of the ship. With such a rigid structure efforts toscale up the size of the ship have been problematic. For example, underhigh sea state conditions there can be significant changes in wavecontours relative to the keel of a vessel, e.g., due to presence of tallwave crests. Such situations can place portions of the keel above thetrough of a wave, resulting in a loss of pressure needed to support theair cushion. Consequently, prior SES designs have generally been limitedto hull lengths less than 100 meters. Under varied sea conditionssurface effect ships with shorter keel dimensions have a reducedfrequency of losing air cushion under high sea state conditions, e.g.,sea states of five or higher. Generally, for this reason, surface effectships are not designed with lengths greater than 300 m.

With the ship 10 functioning as an SES, an air cushion can be generatedalong the entire chamber 36 to place the ship in an on-cushion stateresulting in elevation of the hulls 60 a and 60 b relative to a waterline. FIGS. 11A through 11D are elevation views of the ship 10 deployedas a surface effect ship and illustrating the starboard sides of thecomponent vessels 14 during various modes. In FIG. 11A the vessels 14are shown in level trim with an exemplary water line 170 along the hullscorresponding to an off-cushion state and a first draft. FIG. 11A maycorrespond to the vessels configured in an SES mode or the shipotherwise comprising a series of vessels 14 forming the hulls 60 a and60 b. FIG. 11B illustrates the same vessels in level trim relative tothe water line 170 when the ship 10 is configured in an SES mode and inan on-cushion state characterized by a second draft. As shown in FIGS.11C and 11D, the ship 10 readily exhibits changes in pitch at eachinterface between component vessels. Although FIGS. 11C and 11Dillustrate the ship 10 as a surface effect ship in an on-cushion state,similar changes in pitch among the vessels 14 can occur in anoff-cushion state and when the ship 10 is not deployed as a surfaceeffect ship. The illustrations show possible dynamic orientations ofindividual vessels. The changes in pitch are not necessarily to scale orspecific to a particular speed of the ship 10. The magnitude of suchpitch changes can be a function of both the sea state and ship velocity.

FIG. 12 further illustrates, in a side elevation view, features of theship 10 when deployed as a surface effect ship. In FIG. 12, likereference numbers are used to refer to like vessels and components shownin other figures. The ship 10 as shown in FIG. 12 illustrates additionalfeatures including various platform structures, a main propulsion system178 and water jets 180 located in the rear-most vessel 14 b. Aft liftsystems 184 are also located in the vessel 14 b while forward liftsystems 186 are positioned near the bow in the vessel 14 a. The liftsystems are positioned relatively close to the bow seal 40 and sternseal 44 so that if, during on-cushion movement, seaway displaces one ofthe seals causing partial depressurization in the chamber 36, the liftsystems can quickly force the seal back into a sealing position againstthe water surface. FIGS. 13A and 13B are elevation views of the ship 10shown in FIG. 12, again configured as an SES and illustrating,respectively, the bow 24 and the stern 28.

A feature of the invention is enablement of a flexible ship in severalregards. An important load parameter in the structural design of shiphulls is the vertical bending moment due to seaway, which causes changesin pitch. With a ship formed of individual vessels interconnected with adegree of freedom (e.g., rotational freedom to permit differential heaveor changes in pitch) along the interface between vessels, it is possibleto provide a relatively long and slender ship with less structural massthan would be required if the ship were made of a continuous rigid hullportion, whether a mono-hull or multi-hull, e.g., catamaran, design.Further, the achievable length of such a ship is not limited bystructural requirements of the hull portion because the hull portions ofindividual vessels in the ship can be of a size optimized for theapplication, structural efficiency, minimum mass, carrying capacityspeed, economy or other factors. In fact, the length of the ship and thenumber of interconnected vessels forming the ship can be arbitrarilylarge and, based on structural considerations, without limit.

In another regard, the invention enables custom attachment andarrangement of vessels as well as selective “drop off” of individualvessels at multiple points of destination. Ships according to thedisclosed design options are, essentially, modular constructs which canbe assembled and disassembled to suit purposes of a carrier company.They may comprise mixes of uses among the different vessels which haveheretofore been less practical. For example, a ship may include avariety of vessels of different designs to carry containers loadablewith a crane, roll-on cargo and vehicles, liquids such as petroleumproducts, and passengers. The potential high speed capability combinedwith this carrying flexibility allows a transportation company to assurea customer base of rapid and reliable shipping while accommodating shortnotice changes in carrying capacity. For example, if the companyestablishes a regular schedule over a route for high speed delivery, itcan adapt to fluctuations in the amount of cargo space in demand or thetype of cargo or the number of passengers by changing the type andnumber of vessels in the ship on relatively short notice.

In still another regard, multiple embodiments of the invention enableefficient transport of persons or cargo in a surface effect ship ofarbitrarily large length. As a relatively long and slender ship, e.g.,having a L/B of 10:1 or higher, economies of scale can be achieved, alsoallowing for improved fuel efficiency and transport speeds ranging onthe order of 50 to 100 knots while even higher speeds are technicallyattainable.

Another feature of the invention relates to an improved capability ofoperation under high sea state conditions. By way of example, as shipsaccording to the invention travel into large wave fronts, e.g., withcrests on the order of 10 meters or taller, the initial vessel, e.g., 14a, can be optimized in design to encounter such a condition withrecognition that as subsequent vessels in the tandem series travel overthe wave front the magnitude of changes in pitch will diminish. Thus thelatter vessels in the series will undergo smaller vacillations. Thehulls of the ship 10 can respond to bending moments and, for a givenlength of the ship, e.g., over 100 meters, a continuous air cushionchamber, extending the length of the ship, is not susceptible to aircushion pressure losses of the type which are known to occur for rigidhull designs when displacements, e.g., due to changes in pitch, are ofsuch magnitude as to break the seal of the air cushion region. The ship10 is capable of sustaining air cushion pressure under a wide variety ofsea conditions.

While various embodiments of the present invention have been described,these are provided by way of example only. The illustrated hull portions16 of vessels 14 are of a catamaran design, but other hull designs maybe used in accord with principles and teachings of the invention. Forexample, the hull portions 16 may be of a trimaran design. The vessels14 may be formed with three or even more hulls wherein hulls ofdifferent vessels are formed along common axes to provide three or moreship hulls like the hulls 60 a and 60 b. In surface effect ships of thisdesign, the volumes between pairs of ship hulls can be pressurized toprovide lift.

Numerous other variations are contemplated for designs based on rotationof fore or aft regions of the hulls 20. For the design shown in FIG. 4,the fore and aft regions of the hulls may have circular shapes that comeclose together when two vessels are coupled. That is, one circularshaped surface can nest along another circular shaped surface with eachsurface following a contour along a different one of two concentriccircles. That is, the circular arcs may differ slightly in radius, toallow for tolerances and insertion of sealing materials, while each maybe aligned for rotation about the same concentric center. Thisarrangement includes placing the pin substantially along the commongeometric center of the concentric circles so that each arc rotatesabout the same center point. See FIG. 10A which is a side elevation viewof the spaced-apart vessels 14-1 and 14-2 shown in FIG. 4.

The hull fore region 56 a includes a circular surface contour 192 alonga circle of radius a₁ and centered about a receiving cylinder 194. Thehull aft region 58 a includes a circular surface contour 198 along acircle of radius a₂ and centered about a pin 200 which is positionablein the receiving cylinder 198. In order to bring the surfaces close toone another and allow room for sealing material, a₂ is slightly greaterthan a₁. The pin 200 may be retractable and extendable to selectivelyenter the cylinder after the hull surface contours 192 and 198 arebrought close together in the process of coupling the vessels to oneanother. For this embodiment the pin 200 is shown to be positioned onthe hull aft region 58 a at the center of the circle along which thesurface contour 198 extends. Concealed portions of the lowest deck 22,the second deck 34 and the weather cover 38 are shown with phantom linesto illustrate relative positions of the contours 192 and 198. Thedistance b, from the receiving cylinder 194 to the keel 202 and thedistance from the pin 200 to the keel 202 are shown to be about thesame, e.g., approximately a₁ or a₂, but may be substantially less thanor greater than a₁ or a₂. Vessels 14 constructed in accord with FIGS. 3,4 and 10A are further illustrated in FIGS. 10B and 10C wherein thecircular contour 206 corresponds to the combination of concentricsurface contours 192 and 198 as well as any voids or sealing materialstherebetween.

With reference again to FIG. 10A, in other embodiments the position ofthe pin 200 may be laterally displaced a distance c along the lowestdeck 22 or may be moved up or down relative to the lowest deck 22 bychanging the distance b relative to the keel 202. With reference to FIG.10D, when the pin 200 is so displaced relative to the center of thecircle along which the surface contour 198 extends, the contours,referenced as 192′ and 198′, no longer follow the paths of concentriccircles but rotate about a point 210 where the pin 200 is placed in thereceiving cylinder 194. Further, the surface contours may be modified asshown in FIG. 10D to follow non-circular curves which can comerelatively close to one another when the vessels are running with nopitch. With these variations, movement of the contours 192′ and 198′ mayemulate movement of cams. As shown in FIG. 10D a modest gap 206 mayexist between the contours 192′ and 198′ which may be closed withsealant material to avoid loss of pressure in the chamber during anon-cushion state. However, as the vessels display significant sag, alarger gap 208 can form which may require additional insertion ofsealing material to reduce loss of pressure during the on-cushion state.See FIG. 10E. When the vessels experience such relatively large pitchthere may be a significant but temporary pressure loss. For this reason,the hull connection configuration described with reference to FIGS. 10Band 10C may be advantageous. The aforedescribed variants can be appliedto the embodiments illustrated in FIGS. 7, 8 and 9.

The hinge-like couplings permit rotational freedom about an axis normalto the two axes A and A′ to allow for relative changes in pitch of eachvessel while at the same time inhibiting yawing and rolling motions ofthe vessels with respect to one another. The invention may be deployedwith a variety of other connection mechanisms between individual vesselsthat form the ship. For example, in lieu of the coupling 50 connectingthe vessels 14, vessels could be connected to one another in a tandemarrangement with substantial separation distances between the hulls ofadjacent vessels. In such implementations, the connection mechanism maybe of a type which allows a limited rotational degree of freedom,similar to the rotational geometry of the mechanisms 50, to permitchanges in pitch. However, still other designs are contemplated, e.g.,including designs which allow for changes in both pitch and yaw but notroll, or even a conventional ball joint design which allows for changesin pitch, yaw and roll. Depending on the intended use of the ship, suchalternate configurations may be preferred. For example, a coupling whichallows for changes in yaw and roll could facilitate maneuverability ofthe ship 10 operating as a SES along narrow inland waterways. Further,coupling mechanisms may be designed to selectively allow varied degreesof freedom about the couplings among individual vessels during operationof the ship. In SES applications, with connected vessels havingrespective hulls spaced-apart substantially, e.g., by a meter, theopening between the vessels can be sealed with flexible, e.g.,bellows-like, materials to assure that the chamber beneath the hull canbe suitably and sufficiently sealed to provide positive pressure neededto experience on-cushion movement.

Reference to a pin or a hinge-like coupling and, generally, reference tothe mechanism 50, is not at all limiting of the designs which can effectcoupling of vessels. Many components of varied design may beincorporated to perform similar or additional coupling functions betweenvessels. There may be rotation with limited degrees of freedom or alldegrees of freedom to allow motion about each interface between coupledvessels. Numerous variations, changes and substitutions may be madewithout departing from the scope of the invention. Accordingly, theinvention is only limited by the claims which follow.

1. A ship, comprising: a power system; a plurality of vessels, eachvessel comprising at least two spaced-apart hulls extending from fore toaft of the vessel, each parallel with the other with the twospaced-apart hulls defining a cavity between the hulls when the vesselis afloat, such that when the vessels are connected to one another theplurality of vessels provide a series of interconnected cavities forminga chamber, each vessel capable of occupying a first draft when afloatwithout aid of the power system and a second draft smaller than thefirst draft with aid of the power system, each hull on each vesselconfigured as a portion of a coupling mechanism with fore and aftportions of each hull reduced in width relative to an intermediateportion of the same hull, such that pairs of hull fore portions of twoof said spaced-apart hulls and pairs of hull aft portions of two otherof said spaced-apart hulls can be lapped and connected with one anotherto form complete coupling mechanisms each operable to connect one vesselto another vessel so that the plurality of vessels can form a singleassembly and so power can be transferred between vessels to move thevessels through water in a tandem arrangement.
 2. The ship of claim 1wherein connections between pairs of hull fore portions and pairs ofhull aft portions on different vessels are effected with pins allowingfor rotation of the hulls about the pins.
 3. The ship of claim 1 whereinthe vessels are arranged in a tandem series with a first of the vesselsin the series including a forward flexible seal and a last of thevessels in the series including an aft flexible seal, with thecombination of the seals and the spaced-apart hulls of each vesselenabling provision of pressurized air within the chamber.
 4. The ship ofclaim 1 wherein when the ship is afloat with the plurality of vesselsconnected to one another, the cavities are interconnected to form achamber extending along the plurality of vessels.
 5. The ship of claim 4wherein a bow seal is formed between fore portions of the twospaced-apart hulls of one vessel and a stern seal is formed between aftportions of the two spaced-apart hulls of another of the vessels tofacilitate retention of air pressure in the chamber.
 6. A method ofoperating a ship, comprising: providing a plurality of vessels overwater, each vessel comprising at least two spaced-apart hulls extendingfrom fore to aft of the vessel, each parallel with the other with thetwo spaced-apart hulls defining a cavity when the vessel is afloat;configuring each hull on each vessel as a portion of a couplingmechanism with fore and aft portions of each hull reduced in widthrelative to an intermediate portion of the same hull such that pairs ofhull fore portions of two of said spaced-apart hulls and pairs of hullaft portions of two other of said spaced-apart hulls can be lapped; andlapping and connecting pairs of hull fore portions with pairs of hullaft portions on different vessels to form complete coupling mechanismsto connect vessels to one another so that the plurality of vessels canform a single assembly and so power can be transferred between vesselsto move the vessels through water in a tandem arrangement.
 7. The methodof claim 6 wherein formation of the complete coupling mechanismsincludes connecting the fore and aft portions of different hulls withpins.
 8. The method of claim 6 further including providing a powersystem for enabling tandem movement of the vessels as one ship with thecoupling mechanisms permitting each vessel to undergo changes in pitch.9. The method of claim 6 further including connecting the vessels to oneanother to provide a series of interconnected cavities forming achamber.
 10. The method of claim 9 further including providing sealsabout the chamber which facilitate retention of air pressure in thechamber so that each vessel is capable of occupying a first draft whenafloat without aid of the power system and a second draft smaller thanthe first draft with aid of a power system.
 11. The method of claim 6wherein the coupling mechanisms provide limited degree of freedom sothat the first vessel can only undergo displacement relative to thesecond vessel about a single axis of rotation.
 12. The method of claim 6wherein provision of two spaced-apart hulls for each vessel results ineach vessel comprising a pair of parallel catamaran hulls.